Chinese Script in Mg alloy

Magnesium alloys, as the lightest structural metallic materials are of special interest in implants, automobile, aerospace, and electronic industries. The most common types of these materials are those based on the Mg-Al system. Despite the advantages, Mg-Al alloys have relatively poor mechanical properties at elevated temperatures, mainly due to the thermal instability of microstructure containing Mg17Al12 phase. Accordingly, attention has been directed towards developing new alloys with enhanced high-temperature mechanical properties. This has often been achieved by introducing alloying elements such as Ca, RE, Zn, Sb, and Si, which are capable of forming thermally stable intermetallics in the magnesium matrix.

The effects of 0.7 wt.% Si addition on the microstructural evolution, hardness, creep resistance, and shear strength of AZ61 alloy were investigated in the temperature range 298–523 K. Creep behavior was assessed by impression creep test, and ultimate shear strength (USS) was measured by the shear punch test (SPT).  The results showed that hot hardness, creep resistance and high-temperature shear strength of the base alloy were significantly enhanced with the addition of Si. This was attributed to the reduction in the volume fraction of β-Mg17Al12 and formation of the more thermally stable Mg2Si intermetallic particles. These particles have a Chinese script morphology which reduces ductility but acts as the main strengthening agent in the investigated system, by strengthening the matrix of the base alloy and hindering grain growth during deformation.